Breast cancer (BCa) is the most common cancer among US women. While most women live well beyond their cancer, they remain at heightened risk for recurrence, second primary cancers and many other diseases. Lifestyle factors of diet and exercise as well as the related factor of body weight/composition are strong determinants of recurrence and mortality in BCa survivors, yet most BCa survivors do not meet recommended levels of healthy diet and exercise. The emotional impact of BCa may create a potential teachable moment for positive change by heightening motivation for making healthy lifestyle changes, but assistance appears to be needed for most survivors to make or maintain healthy lifestyle changes following cancer. Thus, effective interventions for facilitating healthy lifestyle changes are critical for improving the health of BCa survivors. Recent research on interventions to improve BCa health behaviors has shown them to be effective but quite time and resource intensive. In addition, interventions have not incorporated the specific psychosocial issues of cancer survivorship. This study will test the first intervention for BCa survivors that explicitly capitalize on the teachable moment following diagnosis to provide motivation for healthy eating and exercise behavior change. The objective is to determine the extent to which, in the teachable moment following BCa treatment, survivor concerns and psychosocial factors can be channeled through a targeted intervention to facilitate adaptive diet and physical activity change. To this end, we developed the Targeted Teachable Moment Intervention (TTMI), based on social-cognitive theory, focusing on lifestyle changes issues, addressing facilitators and barriers specific to BCa survivors and channeling survivorship issues into motivation to make and maintain positive life changes. Pilot data suggest that this is a highly acceptable and potentially effective intervention. The proposed study is a randomized clinical trial of 195 BCa survivors who recently completed primary treatment. All study communications will be mail-based. Outcomes include changes in diet (fruit/vegetable and fat intake), exercise, and BMI at the end of the intervention (4 months) and follow-up (3 months later). The primary aim of the study is to test the effectiveness of the new intervention (TTMI) vis-`-vis standard treatment options (SLM and UC) in promoting adaptive lifestyle change specifically targeting BCa survivors at a teachable moment, facilitating resources and coping skills that enable the women to make positive changes in diet, exercise, and weight management. Secondary aims are to determine the extent to which psychosocial mechanisms (i.e., self-efficacy, meaning, positive affect, coping skills, social support) mediate and moderate intervention effects and to examine the motivation to change over time and across groups. PUBLIC HEALTH RELEVANCE: Given the large and increasing numbers of breast cancer survivors (already over 2 million in the US) and their heightened vulnerability to subsequent illness, effective lifestyle intervention is urgently needed. The goal of the present study, to examine whether effectiveness of a lifestyle intervention is enhanced by explicitly focusing on survivorship issues, could have important implications for the design of future interventions for this population. Effective lifestyle change interventions hold the promise for increasing not only the psychological wellbeing and quality of life of breast cancer survivors but also their morbidity and mortality, thus making a significant positive impact on public health.